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EMERGING INFECTIOUS DISEASESEMERGING INFECTIOUS DISEASES
Bruno B. CHOMEL Bruno B. CHOMEL DVM,PhD
WHO/PAHO Collaborating CenterOn New and Emerging Zoonoses
Department of Population Health and Reproduction School of Veterinary Medicine, University of California, Davis
Wild West Veterinary ConferenceWild West Veterinary ConferenceReno, Nevada. October 8Reno, Nevada. October 8-- 12, 200312, 2003
Emerging Infections
"New, reemerging or drug-resistant infections whose incidence in humans has increased within the past two decades or whose incidence threatens to increase in the near future."
Emerging Infections: Microbial Threats to Health in the United States. Institute of Medicine, 1992.
2
Epidemics Epidemics ofof EEmerging Diseasesmerging Diseases,, 11996996––20020033
Cholera
E. coli non-O157
Multidrug-resistant SalmonellaE. coli O157BSEnvCJD
Cholera 0139
Legionellosis
Yellow fever
Hantaviruspulmonarysyndrome
West Nile fever
Cryptosporidiosis
Lyme borreliosis
LegionellosisLassa fever
Ebola hemor. feverCholera
Monkeypox
O’nyong-nyongfever
Rift Valley fever
EchinococcosisWest Nile fever
MalariaTyphoid
Dengue hem. fever Nipah virus
encephalitis
Influenza A (H5N1)
E. coli O157
Hendra virus
Venezuelanequineencephalitis Diphtheria
Emerging Infectious Diseases:Emerging Infectious Diseases:
Major resources are lostMajor resources are lost
U.K., 1990U.K., 1990--9898: : BSEBSE
US$ 9 billion
TanzaniTanzania, 1998a, 1998::CholeraCholera
US$ 36 million
IndIndia, 1994ia, 1994: : PlaguePlague
US$ 2 billion
Peru, 1991: Peru, 1991: CholeraCholera
US$ 770 million
MalaMalaysia, 1999ysia, 1999: : NipahNipah VirusVirus
Swine slaughteringUS$ 540 million
Hong Kong, 1997Hong Kong, 1997influenza A (H5N1)influenza A (H5N1)
Poultry slaughteringUS$ 22 million
USA, PeriodicallyUSA, Periodically: : E. E. colicoli O157O157Meat recall/destructionUSA, 2001: USA, 2001:
AnthraxAnthraxUS$ 250 million?
ChinaChina, 2003, 2003: : SARSSARSUS$ 25 billion
3
SARS, Spring 2003: Economic Impact on South-East Asian Economy
• HONG KONG: Budget of US $ 15 billion to deal with consequences of SARS• CHINA: US $ 420 million to establish a National Health Surveillance network + US$
240 million for pennyless patients • SINGAPOUR: Program of US $ 230 million to support transportation, hotels and
shops affected by the epidemic.
TOURISMINCOME
FEBRUARY
LESS 40%
MARCH APRIL MAY
Estimated costs of SARS Epidemic worldwide: US $ 60-80 Billion
Emerging and ReEmerging and Re--emerging Zoonosesemerging Zoonoses
• Zoonoses: “The diseases and infections which are naturally transmitted between vertebrate animals and man.” (WHO, 1951)
•Emerging and re-emerging zoonoses: “ Zoonotic diseases caused either by totally new or partially new agents, or by micro-organisms previously known, but now occurring in places or in species where the disease was previously unknown.” (Meslin, WHO, 1992)
4
ZOONOSES and the RISK of DISEASE EMERGENCEZOONOSES and the RISK of DISEASE EMERGENCETaylor et al., Phil. Trans. R. Soc. Lond. B. 2001, 356:983-989.
InfectiousInfectious Human Human ZoonosesZoonoses EmergingEmergingOrganismsOrganisms PathogensPathogens PathogensPathogens
(N=1415) (N=868) (N=175)Viruses/Viruses/PrionsPrions 217 (15%) 165 (19%) 77 (44%)Bacteria/Bacteria/RickettsiaRickettsia 538 (38%) 269 (31%) 52 (30%)FungiFungi 307 (22%) 113 (13%) 16 ( 9%)HelminthsHelminths 287 (20%) 278 (32%) 10 ( 6%)ProtozoaProtozoa 66 ( 5%) 43 ( 5%) 19 (11%)
• 61% of the human pathogens are zoonotic and 12% are emerging pathogens. 75% (132/175) of the emerging pathogens75% (132/175) of the emerging pathogensare are zoonoticzoonotic. Overall, . Overall, zoonoticzoonotic pathogens are pathogens are twice as likelytwice as likely to to be associated with emerging diseases than nonbe associated with emerging diseases than non--zoonoticzoonotic ones . ones . All but one of classified category A biological agents forbioterrorism and most of category B are zoonoses.
Emerging Zoonoses• Some Major Bacterial Etiologic Agents of New Zoonoses Identified Since 1976
• 1976 Capnocytophaga canimorsus• 1977 Campylobacter spp.• 1982 E. coli O157:H7• 1982 Borrelia burgdorferi (Lyme disease)• 1983 Helicobacter pylori and other spp.• 1986 Ehrlichia chaffeensis (HME)• 1992 Bartonella henselae (Cat scratch Disease)• 1994 Rickettsia felis (Murine typhus like)• 1994 E. Equi/A. phagocytophila (HGE)
5
Emerging Zoonoses• Some Major Viral Etiologic Agents of New Zoonoses Identified Since 1990• 1991 Guanarito virus (Venezuelan hemor. fever)• 1993 Sin nombre virus (Hantavirus Pulm.Syndr.)• 1994 Sabia virus (Brazilian hemorrhagic fever)• 1994 Hendra virus (Equine morbillivirus)• 1996 Australian bat Lyssavirus (Rhabdovirus)• 1997 Menangle virus (paramyxovirus)• 1997 Influenza virus H5N1 (Hong Kong)• 1998 Nipah virus (Paramyxovirus)• 1999 Influenza virus H9N2 (Hong Kong)• 2003 SARS (Coronavirus)
6
Emerging Infectious Diseases• Major Factors Contributing to theEmergence of Infectious Diseases
• Human demographics and behavior• Technology and Industry• Economic Development and Land Use• International Travel and Commerce• Microbial Adaptation and Change• Breakdown of Public Health Measures
Institute of Medicine Report, 1992• Bioterrorism
Wor
ld P
opul
atio
n in
bill
ions
(
)
Day
s to
Circ
umna
viga
te (
)
th
e G
lobe
Year1850
0
400
350
300
250
200
150
100
50
2000
0
1900 1950
1
2
3
4
5
6
Speed of Global Travel in Relation toWorld Population Growth
Murphy and Nathanson. Semin. Virol. 5, 87, 1994
7
0
10
20
30
40
50
60
70
80
1790
1800
1810
1820
1830
1840
1850
1860
1870
1880
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
Year
Popu
latio
n / s
quar
e m
ile
Population Density, United States, 1790Population Density, United States, 1790--20002000
3.9m3.9m
281m281m
Source: F.A. Murphy, UCD
Reasons for emergence or re-emergence of zoonoses
Human population increase leading to an increased number of contacts between humans and infected animals.
8
Emerging Zoonoses• Estimated Global Mobile Population
• International Travelers 698 million (WTO, 2000)
• Migrant Workers 70-80 million (ILO, 2001)
• Refugees/Uprooted People 22 million (UNHCR, 2002)
• Undocumented Migrants 10-15 million (ILO, 2000)
• Migrant Victims 0.7 million (IOM, 2001)of Trafficking
SARS PANDEMIC, Spring 2003:Spread of a new Infectious agent through international flights.
More than 30 new infectious diseases caused millions of deaths since the mid 1970’s. As for SARS, epidemiological surveillance is critical (Ebola,Africa; Avian Flu A/H7N7, Netherlands, etc.)
« Infectious Diseases will continue to emerge…»
9
Coronavirus
Spread of a new Infectious agent through international flights.
Incidence of Rickettsial Spotted fever was 14 cases per million for travelers to Africa.By comparison, incidence of Rocky Mountain Spotted Fever in the USA is only 2 cases/million population
In 2000, 27 million Americans travelled abroad9% visited a National Park, 5% camped or hiked, 5% visited sites of ecological interest, and 2% (540,000) traveled to Africa.
10
Influenza A Pandemic 1918-19
Major Epidemics will come back
Influenza pandemics*and recent outbreaks, 1918–2002
Year Colloquial name & subtype affected age group No. deaths
• 1918* Spanish flu (H1N1) all ages 40 million
• 1957* Asian flu (H2N2) > 65 and < 5
• 1968* Hong Kong flu (H3N2) > 65 and < 5
• 1976 Swine flu (H1N1) all ages 1
• 1997 Chicken flu (H5N1) all ages (18 cases) 6
• 2003 Chicken flu (H5N1) all ages (4 cases) 2
• ? Naturally occurring pandemics inevitable ?
. ? Deliberately caused, highly lethal outbreak feasible ?
4.5 million
11
H5N1- Influenza outbreak Hong Kong 1997-1998
H5N1- Influenza outbreak Hong Kong 1997-1998
One million chickens were destroyed Imports from mainland China were stopped
Shortage of poultry occurred in HK
Infectious diseases spread to new areas
Cumulative number of reported HIV cases in theCumulative number of reported HIV cases in theRussian Federation, 1987-2001 (as of June 2001)Russian Federation, 1987-2001 (as of June 2001)
Russian Federation AIDS Centre
0
140 000
1987 1988 1991 1994 1996 1998 2001
number of cases
120 000
100 000
80 000
60 000
40 000
20 000
1989 1990 1992 1993 1995 1997 1999 2000
12
Ebola Hemorrhagic Fever, Africa 1976 - 2003
Ivory Coast1994 (1)
Uganda, 2000-2001 (425/53%)
Gabon,1994 (49/59%) 1996 (31/68%) 1996 (60/75%)2001-02 (60/83%)
Sudan,1976 (284/53%), 1979 (34/65%)
Zaire/Rep. Congo 1976 (318/88%), 1977 (1),1995 (316/81%)2002-03 (143/89.5%)
South Africa, 1996 (2/50%)
Suspected Ebola Cases, by exposure date, Gabon 1996Suspected Ebola Cases, by exposure date, Gabon 1996
02468
101214161820
Num
ber o
f Cas
es
Week 1 Week 2 Week 3 Week 424-30 Jan.24-30 Jan. 31-7 Feb.31-7 Feb. 8-14 Feb.8-14 Feb. 15-21 Feb.15-21 Feb.
Direct exposure
tochimpanzee
13
Ebola hemorrhagic fever, Kikwit, Zaire, 1995 transmission pattern
Ebola hemorrhagic fever, Kikwit, Zaire, 1995 transmission pattern
KikwitGeneralHospital
Kikwit 2Hospital
PATTERN
January February March April May June
Total cases = 316Total deaths = 245 (77%)
JulyInternational Notification early May
Emerging Infections: Technology and Industry
14
Increased International Trade of Agricultural Products.
19500
40
80
120
160 Agricultural Products exports in million tons
1960 1970 1980 1990 2000
Source: WTO, 2000
International trade of agricultural products multiplied by 5 since 1950
Emerging ZoonosesFood-Related Illness and Death
in the United States(Mead et al., EID, 1999)
It is estimated that annually food borne diseases cause approximately:
• 76 million illnesses
• 325,000 hospitalizations
• 5,000 deaths.
15
Emerging ZoonosesChanges in the Factors that Contribute to the Epidemiology of Food-borne Diseases
(Osterholm, 2002)
• Diet• Commercial food service• New methods of food production• New or re-emerging infectious agents• Ethnic preferences• “High-risk” populations, especially increase of immuno-compromised individuals (up to 20%)
Emerging ZoonosesFactors Associated with the “Globalization”
of Food-borne Diseases(Osterholm, 2002)
• Water• Animal feeds and manures• Workers • Transportation• Rodents, other wildlife, insects• Food processing
16
nVCJD and Mad Cow disease (BSE)• nvCJD newly discovered in the UK in 1995• Fatal progressive neurodegenerative disease• Age - 13 and 52 years of age• BSE and nvCJD are caused by the same agent• BSE epidemic in cattle was caused by BSE-
contaminated MBM and source of exposure for humans is food
• No test to detect agent in food or living asymptomaticanimals
• To control nvCJD, control the BSE epidemic
17
BSE and nvCJD: Potential Exposure through International Trade in the early 1990s
Live cattle
Cattle feed andBeef meat for human consumptionPharmaceutical andCosmetic productsBlood and
derivated bloodproducts
Meat and Bones
Human and Bovine Products used in Biology
Rift Valley fever Rift, Yemen et Saudi Arabia, Sept.– Oct. 2000
Infected AreaInfected Area
18
Emerging Infections: Economic Development and Land Use
Raccoon Rabies, United States,
1977-1999(Source: F.A. Murphy,
UCD)
19
Infectious diseases spread to new areas
34
13
12
8
1
1970-1980
48 cases
11
1
31
4
12
535
211
5 1
120 4
37
33
61
1981-1986
338 cases
142320
22120
1163
123
1996-2002
1,705 cases
220
Increasing occurrence of Human Monkeypox in DR Congo, 1970-2001
Exotic Pets andTranslocation
Monkeypox, USA, 2003
Number and percentage of laboratory confirmed monkeypox cases, USA, 2003 (71 cases, 35 lab confirmed)
CharacteristicCharacteristic No.No. (%)(%)State
Illinois (12) 8 (23)Indiana (16) 7 (20)Kansas (1) 1 (3)Missouri (2) 2 (6)Wisconsin (39)17 (49)
Age Group (yrs)6-18 11 (31)19-51 24 (69)
SexFemale 18 (51)Male 17 (49)
20
Exotic Pets andTranslocation
Monkeypox, USA, 2003
Number and percentage of laboratory confirmed monkeypox cases, USA, 2003
CharacteristicCharacteristic No.No. (%)(%)Possible sources of monkeypox exposure Prairie dog(s) 14 (40)Prairie dog(s) & human cases 14 (40)Premises housing prairie dogs 6 (17)
Premises housing prairie dogs and human cases 1 (3)
Clinical featuresRash 34 (97)Fever 29 (85)Respiratory symptoms 27 (77)Lymphadenopathy 24 (69)
Hospitalized 16 (46)
Monkeypox virus: Cell culture, human, negative stain
21
Child, Marshfield Index Case: Primary inoculation site right index finger, 5/27/03. 14 days after prairie dog bites, 11days after febrile illness, hospital day 5.
Child: Secondary lesions 5/27/03, adjacent to primary inoculation site on left hand.
22
Father, 6/05/03, after fevers,
sweats, malaise on 5/31-6/01/03.
Feels well.
Child, 6/5/03, resolving lesions.
MonkeypoxMonkeypox, , USA, 2003USA, 2003
Exotic Pets and Translocation
Monkeypox, USA, 2003
23
Monkeypox virus: Animal Trace back
• All 35 confirmed human cases of monkeypoxassociated with prairie dogs obtained from an Illinois distributor (Il-1) or animal distributors who purchased prairie dogs from IL-1.
• Prairie dogs (about 200) infected through contact with Gambian giant rats and dormice which originated in Ghana. 93 infected prairie dogs traced back to six states.
24
Monkeypox virus: Animal Trace back
• Introduction of Introduction of monkeypoxmonkeypox to USAto USA: Texas animal distributor that had imported 800 small mammals from Ghana on April 9, 2003, containing 762 African rodents, including rope squirrels (Funisciurius), tree squirrels (Heliosciurius), Gambian giant rats, brushtail porcupines, dormice and striped mice.
Black flying fox
Fruit bat (Pteropus alecto)Range: North to Papua New Guinea and eastern islands of Indonesia; South to New South Wales.
In 1996, this species and another the little red flying fox (P. scapulatus), were shown to carry a virus very closely related to rabies virus. Since then, flying foxes were also shown to carry the newly discovered Hendra and Nipah viruses.
(Source: F.A. Murphy, UCD)
25
NipahNipah virus, Malaysia, 1998virus, Malaysia, 1998
Deforestation, urbanization, increased pig production….
Development of antibiotic Resistance
Multidrug-resistant Tuberculosis, 2001
hyperendemicoutbreaks
Approximately 1%of all tuberculosisworldwide ismultidrug- resistant
26
EMERGING, REEMERGING, RE--EMERGING ZOONOSES EMERGING ZOONOSES 1. Dogs1. Dogs
• Bacterial zoonoses:Bartonella infectionLeptospirosisBordetella bronchiseptica infectionSalmonellosis, CampylobacteriosisMycobacterial infectionsBites (Capnocytophaga canimorsus)
Protozoan zoonoses:Leishmaniasis (USA)CryptosporidiosisGiardiasis
EMERGING, REEMERGING, RE--EMERGING ZOONOSESEMERGING ZOONOSES
LeptospirosisLeptospirosisIn the past: mainly serovars: L. canicola,
L. icterohaemorrhagiaeMid 1990s:Increased clinical cases in dogs in USA
. in California: L. pomona, L. bratislava
. in Massachusetts, New Jersey, New York, Michigan: L. grippothyphosa, L. pomona, L. autumnalis
Clinical changes: acute renal failure rather than hepatic insufficiency or coagulation abnormalities.
27
Leptospirosis outbreak among 312 participants,Leptospirosis outbreak among 312 participants,Eco Challenge 2000 *, MalaysiaEco Challenge 2000 *, Malaysia
Eco Challenge
Eco Challenge
USA: 10
Canada: 4
Brazil: 1
Uruguay: 1Australia: 4
France: 4UK: 9
* Expedition race, multi-sport event , 20 August - 3 September 2000, Sabah, Malaysian Borneo
A Global Threat
EMERGING, REEMERGING, RE--EMERGING ZOONOSESEMERGING ZOONOSES
2. Cats2. Cats• Bacterial zoonoses: . Viral zoonoses:
Bartonella infection Cowpox (U.K.)Helicobacter infectionSalmonellosis, CampylobacteriosisPlague (Yersinia pestis)Mycobacterial infectionsBites (Capnocytophaga canimorsus)Chlamydia infection
• Protozoan zoonoses:Toxoplasma gondii infectionCryptosporidiosisGiardiasis
28
EMERGING, REEMERGING, RE--EMERGING ZOONOSESEMERGING ZOONOSES
3. Other pets3. Other pets
. Bacterial zoonoses:Salmonella infections and reptilesSalmonella infections and pet HedgehogsStreptococcus iniae and fishCampylobacter and ferrets
. Viral zoonoses:Lymphochoriomeningitis and hamsters
Reptile-associated Human Salmonella
1944 First Salmonella sp. isolate from snakes.1946 First Salmonella sp. isolate from turtles and lizards.1963 Turtle-associated salmonellosis first described.1972 FDA regulation requiring certification of turtles for sale as
"Salmonella-free."1974 Study shows 300,000 turtle-associated human
salmonellosis cases per year in U.S.1975 FDA bans sale of viable turtle eggs or live turtles with
carapace length < 10.2 cm.1977 CA State regulations ban sale, as above.
History
29
Number of Salmonella Marina Isolates Reported Anually and Number of Iguanas Imported Annually
0
10
20
30
40
50
60
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
Year
No.
S. M
arin
a is
olat
es
0
200000
400000
600000
800000
1000000
No.
igua
nas
impo
rted
No. of S. Marina isolates
No. of iguanas imported
Pediatrics 1997;99:399-402.
30
New and Exotic Pets, Hunting Pens and Game Translocation
• Translocation of infected animals: • bats and rabies • Exotic pets (Gambian Rats) and Monkeypox• brucellosis and reindeer • echinococcosis and foxes
• Translocation of susceptible animals: • ostriches and emus and Western Equine Encephalitis
• Hunting pens: rabies and raccoons
• New and exotic pets: • salmonellosis and iguanas, African pygmy hedgehogs• Egyptian bats and rabies
31
Emerging ZoonosesEmerging Bacterial Zoonoses and the
Immunocompromised Individuals.
• Salmonellosis, Campylobacteriosis
• Rhodococcus equi, Bordetella bronchiseptica
• Bacillary angiomatosis (Bartonella henselae, B. quintana)
• Fish tank Granuloma (Mycobacterium marinum)
• Dog bites (Capnocytophaga canimorsus)
Infectious agent:
Capnocytophaga canimorsus (formerly DF-2, dysgonic fermenter). Commensal organism within the oral cavity of the dog (16%). Fastidious Gram negative rod.
Epidemiology :
C. canimorsus is a common bacterium present in dog mouth. 103 human cases reported between 1976 and 1996. Following dog (91%) or cat (8%) exposure, mainly bites (54% or scratches (8%).Underlying conditions: 61% of cases >50 year-old, splenectomy (33%), alcoholism(24%), neoplastic/ hematologic disease,immunosuppression (5%).
Dog BitesDog Bites Capnocytophaga canimorsus
32
Clinical signs. No major sign in non-immunocompromised patients
. Septicemia, shock, disseminated intravascular coagulation in immuno-compromised patients
Clinical featuresFever (90%), septicemia (94%), septic shock (40%), disseminated intravascular coagulation (32%), meningitis (13%), renal failure (15%), gangrene (14%), thrombocytopenic purpura (14%), cardiopathy (11%), ARDS/Pneumonia (10-12%), endocarditis (7%)….
LetalityLetality: 30%: 30%
Dog BitesDog Bites Capnocytophaga canimorsus
Emerging Zoonoses: Why Now?
• Better tools for diagnosis of fastidious organisms: The Molecular Microbiology Revolution: Hantavirus, Bartonella, etc…
• Epidemiological studies, outbreak investigation• Surveillance systems: Hantavirus, influenza,
leptospirosis, Hendra and Nipah viruses.• Wildlife studies have revealed new pathogens;
new studies done on interaction between wildlife reservoir and domestic animals/humans
• Increased interest in vector borne diseases i.e., tick-borne infections: Ehrlichioses, Lyme, etc.
33
A global threat
A new reality
The risk of deliberaterelease of infectiousagents to cause harm.
Biotechnology is becomingwidely available, whileworld tensions andconflicts remains
Emerging Infectious Diseases: different risks, different response
TB
PNEUMONIA
AIDSMEASLES
DIARRHOEALDISEASES
MALARIA
LEPROSYCHAGAS
FILARIASIS
SCHISTO
ONCHO
GUINEA WORM
POLIO
From mad cows to chickens, primates and
bats
LASSAFEVERHEPATITIS C
CJD EBOLANIPAH
RIFTVALLEY
Avianinfluenza
CHOLERAYELLOWFEVER
MENINGITIS PLAGUE
WESTNILE
FEVER
MONKEYPOX
DENGUE
34
Emerging Zoonoses
• Knowing is not enough; we must apply.• Willing is not enough; we must do.
(Goethe)
Emerging Zoonoses: Control and Prevention
• Recognition • Investigation• Collaboration: Interagency structures • Advanced structures for diagnosis &
surveillance • International & interdisciplinary interventions• Applied epidemiological and ecological
research: Field-trained specialists: Epidemic Intelligence Veterinary Public Health Officers
• Education: Training, technology transfer• Information/Communication
35
Emerging Zoonoses: Control and Prevention
• Recognition: Emerging zoonotic infections first needto be identified.
Traditional approach: identification of a human health problem leading to identification of problems in domestic or wild animal populations (i.e. Rift Valley fever, Q fever, chlamydiosis).New approaches: identification of a health problem in
animals that could be associated with human disease (West Nile virus, USA, 1999).
investigation of potential pathogens in wildlife leading to identification of new reservoirs: Lyssavirusin bats, Australia, Brucella spp. in marine mammals.
Emerging Zoonoses: Control and Prevention
• InvestigationCollaborative field work of multidisciplinary teams
with the support of expert staff scientists and advanced laboratories with molecular biological and immunological technologies.
“Shoe-leather” epidemiology initially to determine main risk factors and potential reservoirs, leading to preventive measures: Hantavirus, Americas, Nipah virus, Malaysia.New approach: Inventory of pathogens carried by various wildlife species, especially when encroached with human habitat: opossums reservoirs of Rickettsia felis, murine typhus, sarcocystis neurona.
36
Disease Surveillance Networks in Asia
Disease Surveillance Networks in Asia
Mekong Basin Disease Surveillance (MBDS)
Pacific Public Health Surveillance Network (PPHSN)ASEA
N
APEC
SEAMIC
SEANET
EIDIOR
37
Emerging Zoonoses: Control and Prevention
• Collaboration: Interagency Structures
• Need for a scientific bridge between various disciplines: zoology, ecology, ornithology, geography, veterinary and human medicines…as illustrated by the early “West Nile fiasco” bird disease? or human disease?…Which agency is in charge?
• Interface between Public Health and Veterinary Public Health at local, national and international levels.
Need for Applied and Basic Research in Emerging Infectious Diseases
- Biology- Informatics
- Nanotechnologies
- Mathematics
38
Emerging Zoonoses: Control and Prevention
• Advanced structures for diagnosis and surveillance,international and interdisciplinary interventions:
Know-How, availability and flexibility
• Applied epidemiological and ecological research: Field-trained specialists: Epidemic Intelligence Veterinary Public Health Officers
Fellowships, training grants, PhDs
• Develop training in molecular epidemiology: The microchip revolution: on site instantaneous
multitests
The need for infectious disease control: 2003
• The right balance between:– Unknown infectious disease risks:
stockpiling and distribution systems of drugs and vaccines for deliberately caused infectious diseases
– Known infectious disease risks: increasing access to drugs and vaccines and strengthening national capacity for prevention and control
Infectious Disease MortalityMorbidity
Deat
hs (m
illion
s)
< 5 years old > 5 years old
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
ARI AIDS DiarrhoeaTB MalariaMeasles
39
Emerging Zoonoses: Control and Prevention
• Education:Training, technology transfer.• Information/Communication
– Enhance communication of information
– Use diverse communications methods
– Establish partnerships to ensure rapid implementation of prevention measures
– An on-line journal for new and emerging disease information
(Source: F.A. Murphy, UCD)
Influenza A(H5N1), Hong Kong 1997: a first attempt at global surveillance and pandemic planning
May 1997 August 1997 September 1997
to January 1998
September 1997 to April 1998
Unknown influenza virus
isolated
Virus identified, WHO Collaborating
Laboratories(Netherlands/CDC)
Epidemiological investigation and
containment, humans and poultry in Hong Kong;Intensified surveillance
worldwidePreparation for
vaccine production
WHO Collaborating Laboratories
40
Emerging zoonoses: Conclusions
• Not major killer or disabling diseases -• transmission cycles complex - animal
reservoirs control and elimination difficult • no top priorities for public health• medical impact in terms of morbidity &
mortality underestimated in all countries • recognised potential for global spread • economic impact considerable • social impact significant• consequences on public health enormous
Control and Prevention of Emerging Zoonoses:
CONCLUSIONS
• Discovery-to-control continuum: discovery/recognition, epidemiologic field investigation, etiologic investigation diagnostics development, focused research, technology transfer, training and outreach, prevention, control and elimination, if possible.
• What made it possible? Better diagnosis tools, awareness (especially of the wide wildlife reservoir), readiness, establishing surveillance systems, collaboration and technology transfer.
• What should be next? Increased awareness and improved curriculum in VPH/ Zoonoses for DVM students. Develop a group of field-trained specialists.
41
Strategies in Prevention and Control:What we need (G.A. Gellert, Nature, 1994;370:409)
• A rapid communication system• A wide-ranging legal authority• A way to get full participation of everyone involved
and to deal with “turf battles” (who gets the credit?) • A coordinated response to the media and a
professional response to public misperceptions• A progressively redefined case definition (for clinical
and epidemiological purposes)• A locally updated clinical management guidelines• A locally updated biosafety management guidelines• Reagents and diagnostic technology transfer to local
sites• A way to shift from emergency to regular response
mode.